Twin wire papermaking machine with guide bodies placed below the suspension level between the converging wires

ABSTRACT

A twin-wire papermaking machine wherein the separate foraminous wires converge towards one another while passing over separately controlled suction boxes and thereafter join together to sandwich the forming fibrous web therebetween as the wires wrap around adjacent suction rolls. Fibrous suspension is contained between the converging wires, and adjustably mounted guide bodies are locate below the suspension level to leave a narrowing gap between themselves and the wires in order to control fiber deposition. The guide bodies may be curved and take the form of rotating rolls or the ends of suspension partitions, and/or a guide body may be arranged in the region where the two wires join such that the suction rolls form the curved surfaces for the narrowing gaps. In this latter embodiment the guide body may include suspension feed conduits therein facing each of the wires. The guide bodies may be oscillated at a frequency of at least 30 cycles per second.

' 1 Apr. 9, 1974 United States Patent Arledter I 1 1 TWIN WIRE PAPERMAKINC MACHINE 162/314 X 162/132 Ploetz et 162/301 X 2,441 169 Roman.... WITH GUIDE BODIES PLACED BELOW 1,722,503 7/929 p THE SUSPENSION L' VEL BETWEEN THE 90,790 6/1965 CONVERGING WIRES Primary Examiner-S. Leon Bashore Hanns F. Arledter, Andritzer Assistant Examiner-Richard H. Tushin [76] Inventor:

Attorney, Agent, or FirmAus tin P. Dodge; Robert A.

Reichsstr. 122, 8046 Graz-St. Veit, Austria Ostmann May 7, 1971' ABSTRACT 221 Filed;

References Cited a guide body may be arranged In the region Where the a tWo'WIre oin Such that the suctlon rolls form the UNITED STATES PATENTS curved Surfaces for the narrowing gaps. In this latter /1930 embodiment the guide body may Raynestm.......I.....-..;.'.Q..... 162/311 X include Suspension feed conduits therein facing each of the Wires. The guide bodies may be oscillated at a frequency of at least 30 cycles per second.

x x N W 2 B6B 2 2 6 .6

2,929,449 3/1960 Mardon et a1... 3,103,463 9/1963 Justus............. 1,875,075 "8/1932 Mason m... 3,149,028

162/303 McKie 9/1964 Robinson.. 12/1971 "ATENTEU APR 9 I974 SHEET 1 [IF 2 ADJUSTING MEANS INVENTOR HANNS E ARLEDTER ATTORNEY PATENTED APR 9 I974 SHiEI 2 0f 2 INVENTOR HANN$ F ARLE 'TER BYQMg M ATTORNEYS TWIN WIRE PAPERMAKING MACHINE WITH GUIDE BODIES PLACED BELOW THE SUSPENSION LEVEL BETWEEN THE CONVERGING WIRES BACKGROUND OF THE INVENTION parts are supported by a perforated plate arranged onv the wire sidenot facing the headbox. Sheet forming takes place under the pressure of the liquid in the open headbox alone. The two single wires converge into the twin wire part, yet the converging wires are substantially vertical. In spiteof thehigh headthus availablein the headbox the known machine is adapted for slow wire speed only.

SUMMARY OF THE INVENTION The invention aims at higher speeds of the wire, furthermore at having the arrangement to each other of the solid particles different in the successive forming zones of the single wire parts.

According to the invention, in the single wire parts, at the wire side not facing the headbox, at least two suction boxes are arranged, adjustable separately from each other in respect of the dewatering effect.

Therefore, sheet forming takes place within a space of continuous liquid consisting in the liquid of the suspension being in the headbox, and in the liquid being in the wire as well as in the'suction box.

The liquid in the headbox may therefore be kept under a very low head, and suction in the suction boxes be created barometrically, that is by suction pipes reaching downward from the suction boxes.

As the suction boxes are adjustable separately from each other, the arrangement to each other of the solid bodies reaching the wire can be kept different in the successive suction'zones. lt'is thuspossible to have layersin which the fibres all are arranged practically longitudinally, and layers in which the fibres are arranged in all directions of the sheet.

The kind of sheet forming can be influenced byanother measure too, that is by guide bodies reaching into the vicinity of the wire and letting free a gap between that body and the wire. The gap converges in the direction of movement of the wire.

It is of great advantage to use a rotating roll as a-guide I body. The surface of said roll can then have the same speed as the'-wire.

Advantageously, a guide body is arranged in-the region, where the two single wire parts join into the twin wire part, the guide body letting free gapsbetween itself and each of the wires.

Furthermore, with advantage, the headbox is divided by partitions into chambers following each other in the direction of the movement of the wire, the partitions letting free a gap between themselves and the wire. If the chambers have separate suspension feed pipes, beside the kind of sheet forming the kind of solid particles can be different from chamber to chamber, that is from zone to zone.

' Advantageously, the guide bodies and partitions are adjustable in respect of their position relatively to the wire. I

The necessary suction for the suction boxes and position of the guide bodies or partitions can be found by a test for each layer.

By changing the position of the outlets of the suspension feed pipes sheet forming can be influenced too.

If at least enact the single wire parts is ascending, the

drawbacks of the known ascending head-boxes are avoided because the end of the ascending part is formed by the twin'wire part inlet.

BRIEF DESCRIPTION OF THE DRAWING I In the accompanying drawingQembodiments of the invention are shown in simplified manner.

FIG. 1 shows a vertical section of a paper making machine, j

FIG. 2 a partial section of another machine, and

FIGS. 3 and 4 sections oftwo further machines.

DESCRIPTION OF PREFERRED EMBODIMENTS The paper making machine shown in FIG. 1 has two single wire parts 2 and 3 for sheet forming, the wires of which parts run into a twin Wire part 1. A common headbox 5 for the suspension 4 to be dewatered is arranged oversaid two single Wire parts 2and 3.

In the single wire parts 2 and 3, atthe wire side not facing the headbox, there are arranged suction boxes 6 through 13 having perforated walls and separately adjustable in respect of the dewatering effect. For this purpose, each suction box is connected with a separate suction pipe 15 having a valve 14.

The twin wire part 1 has foils l6 and may be adapted for some more sheet forming. At the transition from the single wire parts to the twin ire part, suction rolls 17 are arranged. 'At the end of the twin wire part 1, there is a suction roll 18 for holding the formed sheet. A pick-up device .is designated with 19.

The suspension 4 has a surface 4' exposed to atmospheric pressure. In the suspension 4, there is arranged a curved guide body 21 reaching into the vicinity of the wire 2, leaving free a gap 20 between itself and the wire 2'. The gap 20-converges in the direction of the movement ofthewire. I

' Another guide body 22 is arranged in the. region where the two single wire parts join into the twinwire part. The guide body 22leav'es free a gap 23 and a gap- I 24 between itselfand the Wires 2' or 3, respectively.

Besides, the guide body 22 is so formed as to divide the suspension streaming over the wire, into two portions, that is into one portions flowing into the twin wire part 1, and into another portions passing the guide body 22 upwardly.

In the guide body 22, a feed conduit 25 is arranged, leading to the region'where the two single wires 2' and 3 join each other. The conduit 25 serves for feeding additions and has two outletsfacing the wires 2'. and 3',

be changed. I With the paper making machine 34, 35, 33 bypartitions 30; These partitions 30 leave .free a gap between themselves and the wire 2 or 3' respectively. The'ends ,of the partitions 30 facing the respective wirecan be formed as curved guide bodies as described for the guidebody 21.,

The chambers 31 through 35 have separate feed pipes 36 for the suspension to be dewatered. The suspension fed by the pipes36 can have different solid particles suspended therein. This way, the sheet formed on the wires 2' and 3' can have layers of different'solid particles.

As the guide body 21 with FIG. 1 is, the partitions 30 in the FIG. 2 embodiment are adjustable in respect of their position relatively to the wires by means not shown. It is sufficient to adjust theend of the partitions 30, which faces the respective wire.

The paper making machine shown in FIG. 3 has two single wire parts 2 and 3 with ascending wires 2' and 3', respectively. The headbox. S is, at its inlet sides, confined by a wall 37. Theoutlet side of the headbox is formed by the twin wire part 1.

according to FIG. 2, I the headbox 5 is divided into chambers 31,32,33 and The paper making machine according to FIG. v4 has I parts there are arranged deflecting rolls which can beformed as suction rolls. 1

- In the headbox 5 of the single wireparts 2 and 3 there are'two rolls 41 which serve as partitions for the suspension being in the headbox 5. Furthermore, the partof the rolls 41 facing the wire 2' or 3', respectively, forms a gap between itself and the respective wire and serves asa guide body.

The rolls 41 rotate, and the surface of the rolls 41 moves in the same direction as the wire faced by the rolLThe speed of theroll surface can be kept equal to the speed of the wire, creating a stream in the gap which has the same speed as the wire. Thus, in the gap between roll 41 and wire solid particles are laid onto the wire orientated in all directions. By changingthe speed of the roll the laying can be influenced in respect of the orientation of the laid'solid particles.

. In the direction of movement of the wire,'the rolls 41 are preceded. by feed pipes 42 for a suspension or additions. The chamber 33 succeeding the roll 41 is fed by a feedpipe '43. In the region where the two single wire parts join, a guide body 22 is arranged, including a feed conduit 25 for additions. i

As the conduit 25 in the FIG. 4 embodiment opensdirectly into .the twin wire part 1, instead of additions two layers formed in the single wire parts 2 and 3;

In the chambers 31 and 3S, and in the chamber 33 the suspension has different levels 4' and 4", respectively, in the headbox 5.

The drained liquid, especially the liquid containing additions, is re-circled in separate circuits; as shown for one circuit in FIG. 1; the liquid drained by the suction rolls 17 is refined and prepared in a device 43, and then flows through conduit 25 into the headbox 5.

The guide bodies 21 and 22and the rolls 41 can be oscillated with at least 30 periods per second.

there can be introduced filling material between the The suspensions to be dewa tered may contain natural fibres or other particles adapted to form a paper-like sheet. v

I claim: 1 1. In a paper making machine of the type including two endless, travelling wire parts having opposed vertical portions between which theformed web is confined, and head box means common to both wire parts, arranged above said opposed portions; the improvement comprising:

a. at least two convergent inclined perforated bottom walls in said head box, one wire passing over a corresponding one of said walls; b. at least one suction box forming a portion of each of said walls; v 0. means to adjust the absolute pressure maintained in each box; and d. at least two guide means in said head box each having an inclined surface portion proximate to a different one of said wire parts, said inclined surface together with the corresponding wire partdefining' I a narrow gap which gap tapers in the direction of wire movement, said gap having one curved boundary surface, the wire movement causing formation of a stream of suspension through said gap whereby fiber deposition is controlled.

2. A paper machine as defined in claim 1 in which at least one of said guide means comprises a rotating roll extending transversely of the associated wire part and rotating in a direction such that the elements thereof which define saidtapering gap move toward the associated wire part.

' 3. A paper making machine as defined in claim 1', wherein at least one of said'guide means comprises a. a partition in said head box extending laterally with respect to the direction of wire travel,

b. one edge of said partition being the inclined surface portion of the' guide means.

4. The machine defined in claim 1; and

a. Means to oscillate at least one of said guide means at a frequency of atleast 30 cycles per second.

5. The machine defined in claim 1 in which:

a. one of said wire parts includes a' portion within said headbox and having an upwardcomponent of mo- 6. The machine defined in claim 1; and

a. means to move at least one of said guide means so as to vary said gap.

7. A paper making machine according to claim I, in which two of said at least two guide means are located in the region where said two single wire parts join, the inclined surface portion of each of said two guide means being the boundary surface of a gap between itself and a different one of the wire parts.

8. In a paper making machine of thetype including two endless travelling wire parts having opposed vertical portions between which the formed web is confined,- and head box means common to both wire parts,

arranged above said opposed portions; the improved. at least two guide means in said head box each having an inclined surface portion proximate to a different one of said wire parts, said inclined surface together with the corresponding wire part defining Y a narrow gap which tapers in the direction of wire movement; said gap having one curved boundary surface, the wire movement causing formation of a stream of suspension through said gap whereby fiber deposition is controlled,

a feed conduit in said element and having two outlets, each outlet facing a different one of said wire parts and opening into a tapering gap. 

1. In a paper making machine of the type including two endless, travelling wire parts having opposed vertical portions between which the formed web is confined, and head box means common to both wire parts, arranged above said opposed portions; the improvement comprising: a. at least two conveRgent inclined perforated bottom walls in said head box, one wire passing over a corresponding one of said walls; b. at least one suction box forming a portion of each of said walls; c. means to adjust the absolute pressure maintained in each box; and d. at least two guide means in said head box each having an inclined surface portion proximate to a different one of said wire parts, said inclined surface together with the corresponding wire part defining a narrow gap which gap tapers in the direction of wire movement, said gap having one curved boundary surface, the wire movement causing formation of a stream of suspension through said gap whereby fiber deposition is controlled.
 2. A paper machine as defined in claim 1 in which at least one of said guide means comprises a rotating roll extending transversely of the associated wire part and rotating in a direction such that the elements thereof which define said tapering gap move toward the associated wire part.
 3. A paper making machine as defined in claim 1; wherein at least one of said guide means comprises a. a partition in said head box extending laterally with respect to the direction of wire travel, b. one edge of said partition being the inclined surface portion of the guide means.
 4. The machine defined in claim 1; and a. Means to oscillate at least one of said guide means at a frequency of at least 30 cycles per second.
 5. The machine defined in claim 1 in which: a. one of said wire parts includes a portion within said headbox and having an upward component of motion.
 6. The machine defined in claim 1; and a. means to move at least one of said guide means so as to vary said gap.
 7. A paper making machine according to claim 1, in which two of said at least two guide means are located in the region where said two single wire parts join, the inclined surface portion of each of said two guide means being the boundary surface of a gap between itself and a different one of the wire parts.
 8. In a paper making machine of the type including two endless travelling wire parts having opposed vertical portions between which the formed web is confined, and head box means common to both wire parts, arranged above said opposed portions; the improvement comprising: a. at least two convergent inclined perforated bottom walls in said head box, one wire passing over a corresponding one of said walls; b. at least one suction box forming a portion of each of said walls; c. means to adjust the absolute pressure maintained in each box; and d. at least two guide means in said head box each having an inclined surface portion proximate to a different one of said wire parts, said inclined surface together with the corresponding wire part defining a narrow gap which tapers in the direction of wire movement; said gap having one curved boundary surface, the wire movement causing formation of a stream of suspension through said gap whereby fiber deposition is controlled, e. two of said at least two guide means being located in the head box above said vertical portions and defining two gaps, one between each of said two guide means and a different wire part; and f. said two guide means forming a single element and a feed conduit in said element and having two outlets, each outlet facing a different one of said wire parts and opening into a tapering gap. 